Compression compatability [was Re: 10x compression factor]

Maxine Brandt torduninja at
Tue Feb 10 08:17:31 CET 2004

Hash: SHA1

On Tue, 10 Feb 2004 David Shaw wrote:

> This isn't what happens.  GnuPG treats having no compression
> preferences as a preference for ZIP.  This is part of the OpenPGP
> standard.  Thus, it will always use ZIP when encrypting to a PGP key,
> and PGP has ZIP, of course.
> There are occasional problems when someone generates a key in GnuPG
> (thus having a "ZLIB ZIP" preference), then moves that key over to PGP
> for use without updating their preferences.  Programs encrypting to
> that key see the ZLIB preference and use it.

Thanks for the precision, David. That was my understanding of the situation, 
until recently I had this problem occur in corresponding with a PGP 8 user 
whose key was definitely PGP-created. All my messages failed to decrypt 
because of a decompression failure. When I changed the preferences on my key, 
putting ZIP first, the problem disappeared.

The thread I cited was started by a user of both GPG and PGP who had imported 
his GPG key into PGP without changing the preferences, but  the same problem 
was reported in the thread by an organisation which  used only PGP. Strange.

- -- 
My GPG/PGP keys are at:
Version: GnuPG v1.2.4 (GNU/Linux)


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